<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title></title>
    <style type="text/css">
        #box1{
            width: 100px;
            height: 100px;
            border: 1px solid yellow;
            border-radius: 100px;
            background: yellow;
            margin-bottom: 10px;
            background-image: url("img/QQ图片20161010220520.jpg");
        }
        #box2{
            width: 100px;
            height: 50px;
            border: 1px solid yellow;
            border-radius: 20px 20PX 20PX 20PX;
            background: yellow;
            margin-bottom: 10px;
        }
        #box3{
            width: 100px;
            height: 50px;
            border: 1px solid yellow;
            border-radius: 0 20PX 20PX 0;
            background: yellow;
            margin-bottom: 10px;
        }
        #box4{
            width: 100px;
            height: 50px;
            border: 1px solid red;
            background: yellow;
            background-clip:padding-box ;
            padding: 20px;
            margin-bottom: 10px;
        }
        #box5{
            width: 100px;
            height: 50px;
            border: 1px solid yellow;
            background: yellow;
            margin-bottom: 10px;
            box-shadow:10px 10px 2px 1px red;
        }
    </style>
</head>
<body>
<div id="box1">圆形</div>
<div id="box2">圆角</div>
<div id="box3">圆角</div>
<div id="box4">边框背景</div>
<div id="box5">盒子阴影</div>
</body>
</html>